1. Field of the Invention
The invention relates to a radio broadcasting system comprising a transmitter and a receiver for transmitting and receiving at least one program signal and a data signal, the data signal comprising information pertaining to an indicated program signal.
The invention relates to a radio broadcasting transmitter for transmitting at least one program signal and a data signal, the data signal comprising information pertaining to an indicated program signal.
The invention also relates to a radio broadcasting receiver for receiving at least one program signal and a data signal, the data signal comprising information on an indicated program signal.
The invention further relates to a radio broadcasting method for transmitting and receiving at least one program signal and a data signal, the data signal comprising information pertaining to an indicated program signal.
Furthermore the invention relates to a radio broadcasting signal comprising at least one program signal and a data signal, the data signal comprising information pertaining to an indicated program signal.
2. Description of the Related Art
Such a radio broadcasting system is known from the Specification of the Radio Data System (RDS), as published in April, 1992, by CENELEC under Ref. No. EN 50067: 1992. In this FM radio broadcasting system, the program signal is frequency modulated on a carrier, and the data signal is modulated on a subcarrier of 57 kHz and comprises information on a program signal indicated in the data. This indicated program signal can be the accompanying program signal or a program signal related to the accompanying program signal. This information comprises an identification of the network the indicated program signal is broadcast on, alternative frequencies on which the same program signal can be received, linking information for a switch-over to another network comprising traffic information related to the network broadcasting the program signal, etc. In general, this information relates to an infrastructure for the same or related program signals. This means that when a data service is incorporated in the information in the data signal, this data service will share the same infrastructure as the program signal.
An object of the invention is to provide a radio broadcasting system in which a data service in the data signal is no longer restricted to the infrastructure related to the program signal.
A radio broadcasting system according to the invention is characterized in that the data signal further comprises data of a data service and information pertaining to said data service.
A transmitter according to the invention is characterized in that the data signal further comprises data of a data service and information pertaining to said data service.
A receiver according to the invention is characterized in that the data signal further comprises data of a data service and information pertaining to said data service.
A method according to the invention is characterized in that the data signal further comprises data of a data service and information pertaining to said data service.
A signal according to the invention is characterized in that the data signal further comprises data of a data service and information pertaining to said data service.
The invention is based on the recognition that by adding data of a data service to the data signal together with information on the data service, it is possible to broadcast the data service on a network of transmitters substantially differing from the network broadcasting the program service. In this way, for example, the area coverage for the data service can be made different from the area coverage for the program signal. This results in increased flexibility for a service provider, providing the data service. The information pertaining to the data service may comprise an identification of the data service, alternative frequencies on which the data service is also being broadcast, information on the area coverage of the data service, etc.
An embodiment of the radio broadcasting system according to the invention is characterized in that said system is the RDS system. An example of a radio broadcasting system wherein the invention is of particular advantage is the Radio Data System.
An embodiment of the radio broadcasting system according to the invention is characterized in that the data signal is organized in groups having a group type code for distinguishing between different types of data, and groups having the same group type code are used for transmitting the data of said data service and the information pertaining to said data service. By this measure, the data and the information of a particular data service are grouped together using the group type code. This allows, at the receiver, a simple and effective recognition of groups of data belonging to the data service. An example of such a code is the Group Type Code as used in the Radio Data System.
An embodiment of the radio broadcasting system according to the invention is characterized in that a group comprises a data bit for distinguishing remaining data bits as either comprising data of the data service or information pertaining to said data service. This allows a simple way for a receiver to distinguish between the data of a data service and the information pertaining to the data service.
An embodiment of the radio broadcasting system according to the invention is characterized in that the information pertaining to said data service comprises information on a related data service. In this way, it is possible to link a data service to other data services which carry related data. Now it is possible to gather desired data which is transmitted on several data services and consequently on several networks.
An embodiment of the radio broadcasting system according to the invention is characterized in that the information pertaining to the related data service comprises switching information for switching the tuning of the receiver to a frequency for receiving the related data service. This allows a reliable switch-over from one network carrying the data service to another network broadcasting the related data service. Such switching information may comprise alternative frequencies on which the related data service can be received, an identification of the service provider providing the related data service, an identification of the related data service, etc. The switching information can also comprise trigger information for the switch-over. In this case, a receiver can determine the moment a switch-over should take place and possibly the duration of the switch-over as well (if such information is provided).